Amstrad PC9486 Troubleshooting Guide
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Fault-finding notes for the Amstrad PC9486 range. Amstrad's service documentation for these machines has not been published, so the table below deals with the problems that the 1994 reviews, Amstrad's own description of the hardware and Cliff Lawson of Amstrad describe: lost setup, memory, hard disc size limits, processor upgrades, the display and the multimedia model's memory use.[1] Case layout and parts are in the Amstrad PC9486 Maintenance Guide.
Preliminary checks
[edit | edit source]- Check the mains lead and the monitor lead, and that the monitor is switched on.
- Look at the front of the case: the model's configuration is written there, and the hard disc type is on a sticker at the back. Note both before changing anything in setup.[2]
- Check the turbo button and the three front-panel lamps.[3]
- Open the case only after unplugging the system unit; the drive cables lie across the SIMM sockets and one expansion slot, so note where every cable goes.[4]
Symptoms
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| Setup lost at every switch-on; the hard disc is not found | Flat or leaking CMOS battery. A Vogons reply places it on the case near the power supply, with a cable to the main board[5] | Replace the battery and check its lead and connector for corrosion. Re-enter the hard disc type from the sticker on the back of the case (type 44 on the machine Joystick photographed)[2][3] |
| Wrong memory count or a memory error after an upgrade | SIMMs of the wrong kind for the free sockets, or non-parity SIMMs | The board has four standard SIMM sockets and one 72-pin socket, up to 48 MB in all.[3] Lawson advises parity SIMMs unless the BIOS has an option to turn off parity checking[1] |
| Memory error after the case has been open | A SIMM or drive cable disturbed while reaching the sockets | Reseat the SIMMs and every drive cable that was moved[4] |
| A hard disc larger than 512 MB shows the wrong size or is not usable | No logical block addressing support in the BIOS of the earlier machines of this generation | Install disc manager software such as Ontrack's Disk Manager, which Lawson notes came with most drives of that size, or use a smaller drive[1] |
| Machine dead or unstable after a processor upgrade | Wrong voltage part. Lawson describes these machines as 5 V 486 boards | Fit a 5 V part or an upgrade processor with its own 5 V to 3.3 V regulator. Check that the ZIF lever is closed and the heatsink is back on[1][3] |
| A 486SX machine will not take a maths co-processor | There is no 487 socket | Replace the 486SX with a DX processor[3] |
| Slower than expected | No cache fitted; many machines were sold without it, including the DX2-50s tested by Joystick and Science & Vie Micro | Check the turbo button, then fit cache chips in the user-installable sockets, up to 256 KB[3][6] |
| Mouse dead at start-up, with a graphic error screen | The Amstrad Desk Top start-up program catches the mouse driver's error when the mouse is badly connected | Check the PS/2 mouse plug at the back of the main board[3] |
| Games on the multimedia model report too little memory | The default start-up leaves 509K of conventional memory | Start from a boot disc or edit CONFIG.SYS to free memory[4] |
Display
[edit | edit source]- The SVGA is a Cirrus Logic 5426 with 1 MB of video RAM on the main board, so there is no video card to reseat.[4][3]
- A blurred picture above 640 × 480 on the standard monitor is not a fault. Science & Vie Micro found that the 0.39 mm dot pitch screen supplied with the DX2-50 it tested was not sharp above that resolution.[6]
- For faults inside the monitor, discharge the tube first; see CRT Discharge Procedure.
Multimedia model
[edit | edit source]The multimedia PC9000 has a Sound Power Pro 16 card, which PC Review describes as a proprietary card compatible with the Sound Blaster Pro, and a Sony double-speed multisession CD-ROM drive.[4] If sound or the CD-ROM drive stops working after the start-up files have been edited to free memory, check that the drivers for both are still loaded.
Rebuilding the software
[edit | edit source]MS-DOS and Windows were supplied on floppy discs as well as pre-installed, and the Amstrad Desk Top includes a tutorial on adding expansion cards and repairing a damaged disc.[3] Keep the original discs with the machine.
Related pages
[edit | edit source]- Amstrad PC9486 · Amstrad PC9486 Maintenance Guide · Amstrad PC9486 Capacitor Replacement Guide
- Hard Drive Maintenance and Repair · Floppy Drive Repair · Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 Cliff Lawson (Amstrad plc), "Recent AT PCs" (newpcs.htm), from his Amstrad support pages at web.ukonline.co.uk/cliff.lawson, as preserved at freetimeweb.nl. Retrieved 2026-10-21. Lawson uses a 9486 himself; general guidance for the 6486 to 9555 machines on 72-pin SIMMs and parity, IDE drives over 512 MB on machines without LBA, and 5 V 486 upgrade processors with 5 V to 3.3 V regulators.
- ↑ 2.0 2.1 "Amstrad PC 9486 SX-25: modeste à tout point de vue", Science & Vie Micro no. 117, June 1994, p. 122. Scan at archive.org/details/science-et-vie-micro-117. Retrieved 2026-10-21. The configuration printed on the front of the case and the hard disc type on a sticker at the back, so a lost setup can be restored.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 "Les PC 9000 d'Amstrad", Joystick no. 47, March 1994, pp. 36–37. Scan at archive.org/details/joystick047. Retrieved 2026-10-21. Power, turbo and reset buttons and three lamps on the front; PS/2 keyboard and mouse sockets on the main board; ZIF socket with the P24T OverDrive; AMI BIOS; no 487 socket; user-installable cache, none on the DX2-50 tested; four standard SIMM sockets and one 72-pin socket, 48 MB maximum; the Amstrad Desk Top start-up program, which shows a graphic error screen when MOUSE.COM reports a badly connected mouse; MS-DOS and Windows supplied on floppy discs; a photograph of the rear panel with a "Hard disk drive type 44" sticker.
- ↑ 4.0 4.1 4.2 4.3 4.4 Christina Erskine and Dean Evans, "Amstrad's back!", reviews of the Amstrad PC9000 Multimedia and the Amstrad 9486 (66 MHz 486DX2), PC Review issue 30, April 1994, pp. 20–21. Scan at archive.org/details/pc-review-030. Retrieved 2026-10-21. Version 3 ZIF socket with the P24T pin-out; Cirrus Logic graphics with 1 MB on the main board; drive cabling obscuring one of the five slots and making another hard to reach; SIMM sockets that may need the drives disconnected to reach; Sound Power Pro 16 card and Sony double-speed CD-ROM drive in the multimedia model; 509K of conventional memory free after the multimedia model's default start-up, so games need a boot disc or an edited CONFIG.SYS.
- ↑ Vogons forum, "Amstrad pc9486 manual.", 2024. Retrieved 2026-10-02. A reply placing the CMOS battery on the case near the power supply with a cable to the main board.
- ↑ 6.0 6.1 "Amstrad PC 9486 DX2-50: du bon qui s'affiche mal", Science & Vie Micro no. 116, May 1994, p. 64. Scan at archive.org/details/science-et-vie-micro-116. Retrieved 2026-10-21. Loose cables blocking access to the SIMM sockets; display on a local bus; ZIF processor socket; no cache memory and a slow hard disc on the tested machine; a 0.39 mm dot pitch monitor that is not sharp above 640 × 480.